Manager Thomas Tuchel "doesn't blame" N'Golo Kante and Ruben Loftus-Cheek for missing Chelsea's United States tour because of their vaccination status.
"We don't blame people and don't put the finger on them," said Tuchel.
The midfielders will miss a week of pre-season training with the squad in Los Angeles and three friendlies.
The Blues face Mexico's Club America in Las Vegas on 17 July, Charlotte FC at their Bank of America Stadium on 21 July and Arsenal in Orlando on 23 July.
"There's a personal decision to take and both of them took their personal decision," added Tuchel.